Engine



J. DOLZA ET AL Sept. 18, 1956 ENGINE 2 Sheets-Sheet 1 Filed Dec. 31. 1954 .Sept 18, 1956 J, DQLZA ETAL 2,763,252

ENGINE Filed Dec. 51, 1954 i 2 sheets-sheet 2 com I United States Patent() Uhr..

2,763,252 ENGINE John Dolza, Davirsburg, George P. Rfursom, Berkley, Donald C. Unger, Grosse `Poin`te Woods, Mich.. as- Siglmrs .to General Motors Coloration, .Detroitl Misha acorporaton of `Delaware Application December 31, 195.4, Serial No. 479,108.

.1.3 sans. tcltlzsflzz) The present `invention relates to internal combustion .engines and more particularly to .thermostatic 'ing the charge to improve theevaporation v`and mixing of the fuel particles ,into the charge. Although'thermos'tats `have been provided forvactuating such chokes'ands'toves,

they have not accurately and reliably senseduthef'engine temperature. In addition, ithas been the-practice here- Itofreto employ `a separate thermostat for'. actuating the heat valve-andthe choke valve. As a. `resulttheee valves may moveindependently of each other andthusthepositions of the valves may notnbeproperlycoordinated Iwith each other.

vIt is now proposed to provide meanswhich will accurately sense the engine temperature and automatically actuate the engine accessories suchas thechoke .andstove 1in response to the enginetemperature. fhisis to:be accomplishedby providing thermostatic means Whichinay have a portion thereof disposed in intimate heat exchanging relation-with the engine `cooling .system y andor r a portion that'is in heat exchanging relation with the engine exhaust gases. Thus the thermostaticmeansy/ill provide a very accurate-index of thelengine temperature. .139th the choke andthe stove fmay be .actuated -bythismeans -from this common thermostatic means. .Qonsequently, fthe operation of thechoke and stove will .be corelatedwith each other fto insure Y theirk functioning .togethe common objective. YiEven though the choke an tove l -vves may be Yoperated-bythe commonfthlermostatpfthey Y Amay be connected to-the thermostatbyalinkage system v that Vwill lcause-the -chokeand stove tobecome operative and/or inoperative in any .desiredsequence In the two sheets of drawings: v

Figure l isafragmentar'y .Sdeview of amengineyembodying one form of the present invention .with'pportions .thereof-being broken. away.

other form of the invention.

.Figure f3 is an. @ad viewtsksn. Substantially alasstth plane of line 3.-3 .in Figure 2. i

lFigure 4 is aside View of anotherformofhthermostatic meanssrnbsdyins the prsssriffivsnfien- Figure'S isa sideview of anothereform ofdthermostatic means embodying the presentinvention.

'Referring to the drawings in more 'detail,the present invention maybe adapted for actuating anysuitableengine `accessories in. response -to the 4engine 10 ...temperature Iltwever for the purposes of illustration, in the present instance itis particularly adapted for actu-ating control means on an engine induction system 12.

' This induction system 12 may include anyintake manifold 14and ahousing 16 that is mounted on top of the manifold 1 4. The intake manifold f4 which may be disposed on .top oftheengine 1i) includes a plurality of distribution passages thatrcomrnunica'te with the combustion chambers' anda carburetor riser 20'that communicates with the distribution passages. A portion of the 'coolant jacketi22 be'provided in the manifold to contain a portion of `the liquidin the cooling system. Th'e coolant inV thisjacket 272 maybe discharged through an o utlet to be cooled by a radiator ory other'suitable 'heat exchanger.

A so-ealled downdraft carburetor 2`4`may be'mounted `on the carburetor riser 20. A fuel mixing passage 26 may extend'verti'cally l"through the carburetor 24 for mixing'the fuel particles with theY air as it flows therethrough. "A choke valve --28V may be mounted on'a valve Vshaft 30 extending .across the intake end of the fuel mixing passage 26. Thusiby moving aT lever 32011 the end of the Vshaft 30, .thechokevalve 28 may be rotated to vary the air-fuel ratio.

The-housing 16 may b e secured on top of the manifold 14 to form an vair cleaner-silencer assembly ythat encloses'both the carburetor 24 andthe fuel pump 34. A

.filter element 3 6 may be horizontally disposed in the hous- :ing v1 6 to .form an upper .compartment V38 and a lower compartment 40 onthe opposite sides thereof. The carburetor 2 4 may .be disposed-inthe lower compartment 40 with the intake of the .-fuel` mixing passagev extending .through the lter element 36 to communicate withthe upper compartlrlent- An extension .42 may be formed on one wall ofthe housing 16 to project forwardly from the assembly and form an jintake passage 4 4. YThe present intake passage ,4.4 .terminates adjacent aportion .of the exhaust system suchas `an .exhaust .crossover pipe 46 that'interconnects the exhaustmanifolds on the opposite sides of the engine l1.0. Ashroud f4.8,may.be disposed in spaced relation to t4the .lfQ-S.Sii"verljzfi'p-e 4.6 to form a heating passage 50 having the opposite .endsthereof opento the atmosphere. An irP-!` 4 8 1to in terconnect the intakepassage 44 with the heating efSZmaybe providedin themiddle of the shroud passage Stlformed by. the .shroud 48.

. Iheoutenendof thein'take passage 4.4 may include a .nectangularopening 5 4 that is positioned adjacent the `aperture andfalso communicates directly. .with the atinos'phere. vA buttertiy valvef56 may be' secured to a pin 50 that extends horizonta lly across this opening 54'to rotate with the pin 58. Alever .59 may-be provided .on

the end` of the shaft 58 for moving thevalve 5.6. When this heaftvalve in theclosed .Or'vertical position. the rectangular opening 5 4 will he closed andthe intake passage44will be interconnected with the .heating passages() .by means ofthe aperture 52. Accordingly, air flowing inwardly from the .opposite ends of the heating passage 5 0 will lie-:heated therein by the` exhaust gases in the crossover pipe46ibefore airenters the intake passage 44. Thus the air .wil-lube preheatedbefore the fuel is atomized into .thechargeand the amount of mixing of the fuel into the .changefwilh .accordingly, be greatly increased.

Vlhsnthev heatvalve S6-is in the open or horizontal position asshown in-Figure 2,.air may lHow from the atmosphere .through the opening 54. The air entering through-the `.upper portion of the opening will flow directly :iintofthe .intake .and theinduction system y12. Thevair .entering-through kthe lower .portion of the opening 54 `will-flow into the heating passage `5.0 and out through .the .opposite ends. This vwill not only reduce the amount of heating of the, chargebut, it will also coolilneexhaust 3 crossover pipe 46 and the surrounding structure to prevent excessive deterioration thereof.

In order to automatically position the choke valve 28 and the heat valve 56, thermostatic means 62 may be provided which are responsive to the engine temperature. ln the embodiment shown in Figure 1, the thermostatic means 62 is disposed in a chamber 64 formed by a housing 66. This housing 66 is preferably positioned so that at least one wall of the chamber 64 is in heat exchanging relation with the coolant contained in the cooling system. Thus the temperature of the atmosphere inside of the chamber 64 will be effected by the temperature of the coolant. l

A pair of tubes 68 and 70 may be provided that communicate with the chamber 64 for transferring heat from the exhaust system to the chamber 64. One end of the rst tube 68 may communicate with the heating passage 50 while the opposite end communicates with the chamber 64. The second tube 70 may have one end thereof communicating with the chamber 64 while the other end projects into the fuel mixing passage 26 anterior to the choke valve 28. If the tube is properly positioned, the pressure in the tube 70 will be a function of the volume of the air flowing therethrough. Thus as the volume of the air owing through the mixing passage 26 increases, the vacuum will also increase. Accordingly, a pressure differential will exist between the opposite ends of the tubes 68 and 70 that will result in the heated air in the heating passage 50 being drawn through the tube 68 into the chamber 64. It is therefore apparant that the temperature of the air in the chamber 64 formed by the housing 66 results from the heat transferred from the cooling jacket and the heating passage. As a result the temperature in the housing 66 will be a function of both the exhaust temperature and the coolant temperature. By varying the amount of heat transferred from cach source, the effectiveness of the two temperatures may be controlled.

The thermostatic means 62 may be provided in the chamber 64 so as to be responsive to the temperature therein. As a consequence the thermostatic means 62 will give an indication of the coolant and exhaust temperatures. may be employed, in the present instance it includes a bimetallic spring 72 that is spirally disposed about a horizontal shaft 74 and has the inner end thereof secured to the shaft 74. The shaft 74 may extend through the chamber 64 with one end thereof projecting from the housing 66. A lever 76 may be secured to this end to rotate with the shaft 74. A pair of links 78 `and 80 may be secured to the outer end of this lever 76 and to the levers 32 and 59 on the choke and heat valves. Thus as the spring 72 rotates the shaft 74, the choke and heat valves 28 and 56 will be opened.

Means may be provided for varying the tension of the spring 72. The outer end of the spring 72 may be secured to one arm 82 of a bell crank 84 that rotates about the shaft 74. Another arm 86 of the bell crank 84 may' be connected to a piston 88 by means of a piston rod 90. This piston 88 may be reciprocably disposed in a cylinder 92 horizontally disposed in the chamber 64. The second tube 70 may communicate with the interior of this Although any suitable thermostatic means 1 cylinder 92 for causing a partial vacuum to be applied to at least one side of the piston 88. Thus as the volume of air flowing through the induction system 12 varies, the bell crank 84 will rotate and vary the tension of the spring 72. It has been found preferable to vary the tenj from the heating passage 50 into the chamber 64 and out through the tube to the carburetor 24. l

By properly proportioning the size of the tubes 68 and 70 and the amount of heat transferred from the coolant to the chamber 64, the comparative effectiveness of the two temperatures may be varied to provide any desired co-relation therebetween. It has been found advantageous to provide enough heat transfer from the coolant to the chamber 64 to cause the spring 72 to open the valves 28 and 56 when the coolant is near normal .temperature irrespective of the exhaust temperature. As-

a result if the engine 10 is inoperative long enough for the exhaust temperature to drop, the valves 28 and 56` will not close until the coolant temperature has also` dropped. Thus the choking and heating action will not occur unless there is actually a need therefor. It should be noted that by properly positioning the levers 32, 59'

and 76 and links 78 and 80, it is possible to cause the two valves to open either simultaneously or in some predetermined relationship. In the present instance it has been found preferable to so proportion the levers that the heat valve 56 will open faster than the choke valve 28. However, it should be understood that the reverse of this may be true. It may thus be seen that both the heat valve 56 and the choke valve 28 will be controlled by a common thermostatic means which are responsive to both the coolant temperature and the exhaust temperature. This will insure a consistent relationship beween the two valves as well as the optimum amount of heating and choking.

Another embodiment of the present invention is shown in Figure 2. This embodiment is similar to the rst one in that it is adapted to be employed on an engine having an induction system 112 that includes an intake manifold 114 and a housing 116 mounted on top of the manifold 114. A portion of the cooling jacket 122 may be disposed in the manifold 114. A carburetor 124 may be disposed inside of the housing and have a fuel mixing passage 126 extending therethrough. A choke valve 128 may be mounted on a shaft 130 that extends across the inlet of the fuel mixing passage 126. A lever 132 may be secured to the end of the shaft 130 for positioning the choke valve 128.

An intake passage 144 may be provided which terminates adjacent an aperture 152 communicating with a heating passage and having an opening 154 communicating with the atmosphere. A valve 156 may be mounted on a shaft 158 for opening and closing the aperture 152 .and the opening 154. A lever 159 may be provided on the end of the shaft 158 for positioning the valve 156.

In this embodiment the thermostatic means 162 comprises a device containing a material with a high c0- efcient of thermal expansion in one end and a plunger 165 that projects from the other end. The first end may be disposed in a passage 167 that extends through one wall of the engine into the cooling jacket 122 so that the thermally responsive material will be disposed in the coolant. Thus the thermostat will be in intimate heat exchanging relation with the engine coolant. Thus even though the thermostat 162 is disposed inside of the engine, the plunger 165 will project upwardly to produce an external signal of the engine temperature. A retainer member 169 may be secured to the engine 110 to engage a collar 171 and thereby retain the thermostat in the passage 167.

A bracket 173 may project upwardly from the top of the retainer 169 to pivotally support a bell crank 175. One arm 177 of the bell crank 175 may rest on the plunger 165 while another arm 176 projects substantially vertically upwardly to receive a pair of links 178 and 180 `similar to those in the first embodiment. The opposite ends lof these links 178 and 180 may be connected to the levers 132 and 159 on the choke Valve 128 and the intake valve i 156. Thus an increase in the temperature of the coolant will cause the bell crank to move in a counterclockwise direction and move both the heat valve 156` and choke-valve` 128 to the'open 1- position: Asv pointed out above; the length'v of' the' levers 132' and1 159" and; the 1inks'1'78' and ISU-may be varied to' move thevalves 128'and 156 in any desredpredetermined'relationship to each other.

A'further embodiment ofthe present invention is shown inFigure 4.

This embodiment like the rst two is'adapted to be employed on anengine' 210 having an'inductionV system withachoke valve andasheat valve; A' housing 212 may besecured' to theengine 210 to form a' chamber 214 havingat leastonewall thereof lin `heat exchangingrelation with" the engine-cooling system 216'." A bathe 218l may be horizontally disposed inside'the `housing212`to divide the chamber 2,14 into an upper compartment 220 and a-'lower compartment-222. A 'Di-metallic spring 224 may be spirally disposed about a shaft 226 that extends through the upper compartment 220 with the Iin ner end thereof being' secured to the shaft 226; A leverV 22,8 may be'secured to the end of the shaft 226 to rotate therewith'. Thus as the spring` 224 expands and contracts, it will movethe lever 228;` A pair of links 230 and 232 may be providedv that interconnect the lever 228'With a heat rvalve and achoke valve.' The opposite end of the spring'v224- may be secured to' one arm of av lever 234 that swings aroundthe shaft 226and`is connected to a piston 236fby means of a piston rod 238; This piston 236 may be reciprocably disposed in acylinder 240 in the upper compartment 220. The cylinder 240V may yhave-one endthereof .connected to a portion of the induction system by means of a conduit 242 and a tube 244 may interconnect theupper compartment 220 with a source of heat suc-h as a heating passage that is in heat exchanging relation with the exhaust system; Thus hot'air will-be drawn intov the upper compartment 22'0 .to heat the spiral spr-inig224fas a function ofitheexhaust gas'temperature, forf'openingand vclosing of the chokeiandfheat valves. Asfthevolume of the air' owing through the induction system varies, the piston 236-"may move and vary the spring tension. Thus the valves may open' more readily when there .is atlarge volume of air owingthrough the induction system.,

Ay secondthermostatic element 246l may bel provided in the lower compartment 222 1inheat exchangingV rela'- tionwith the: engine cooling system216. In the present instance-.this 2 element comprises'a U-shaped vbi-metallic spring'sZAS that 'has one arm 2501. thereof 'engagingr the engine andilthe other arm 2521 projecting'through anV openinlga254iinthebafe 21a.A Thearm252 may: bei connected toioneLer-id of. a: stop; 256that is 'pivotallymounted onla'pntintheuppercompartment 220. The 0p- .posite end' ofthestop. 256` maybe positioned tostrike 'mshonl-derfon' thelever234 and limit thevamount oli' rotation. in a counterclockwise. direction.

When thefenginecoolantriscold, thev spring 248 will contract rand'crotate the stopi256 f counterclockwise. This willzmove the stop 2a'6raway from the shoulder 260fand allow thelever '23.4 =tomove in. either direction. Thus if theA heat transferred intoy thetuppercompartment 220 from the'rexhaustigasesis small,`. the spring 224maylclose the choke; and heat valves provided' thevolurne of airV flow in Lthe'induction system-is not large enoughi to movefthe piston 23.6V and modify the springsaction. When the coiolantbecomes hot,l lthe spring 248 will open up and movesthe stopl256rovertoengage the shoulder 260. Thus evenf-if 'the exhaust temperatureis'below normal, the stop 256 will prevent the thermostat closing the heat and choke valves `and Scausing unnecessary heating.

Another embodiment of thel present invention is illus-tratedin Figure 5.l lnthis embodiment the` thermostat '300i includes a=bimetallic7spring 302disposed in achamber 394i formed -bya housing 3h65 Oneend of the spring 3l2`m-ay be securedto a-shaft-308 that extends through the chamber 304 and "has a lever '310V on 'one' end thereof.

`Aili'nk 312,1 may 'haveone end thereoffconnected to'this lever 3310 andtheother end adapted' to -aetuate'acontrol valve such as the choke. When .the yspringHG2/becomes hot it will `cause the llever 310m move clockwise-and when itV becomes cool, it willv causethe lever 310 to move countercl'ockwise. A pair of' tubes S14-and 36 may be provided for interconnectingthe chamber 3ii4with-the induction system-and: a source of heat such as aheat# ingpassagewhich'is in heat exchanging relation with t-he exhaust system, Thus the spring 302l may position the choke valve inresponse to the exhaust temperature.` A piston .SiS maybe disposed in acylinder 320 and connected to the opposite end ofthe spring 302; Thusif the tube 314 from the induction system communicates -with the cylinder 320, the springtension may-be varied'in response to the volume of air flowing through-theinduction system.

A second thermostatic element may be provided for controlling any additional valves such-as the heat valve. This thermostaticV elementwhich may be of any'desired variety 'comprises a bi-metallic 'U-shaped spring'322 ywhich isl disposed inside of a shield 324. One arm 326 yofthe spring 322fis secured to the engine to bee-in heat exchangingrelation With-the coolant" in the engine cooling'system 328`an-d -thef other end of thisspring' 322 engages one arm of` a bell crank 330. A link 332 maybe connected-to another arm onvthe bell crank 330 for inter-L connectingv the-.bell crank with a valve suchas the heat valve.

It.isthus.seen that thermostatic means areprovided such. Vthat if the exhaust temperature is` belownormal, the chokevalvetwilltbe closed. to enrich. the fuel charge andiftthe: coolant temperature is below normal, the heat valve will. beA closed. toheatthe Vincoming Icharge.

Ithas been foundithatzwhen the engine-is inoperative the exhaust. temperature wili drop considerablyfaster thanlthe engine coolant temperature; Thus after the en?-y gine has been .idle for a `short period of time, the exhaust temperature may be. lowfen'oughto cause the spring302 toA bias. the choke valve tothe closedlposition even though theenginescoolant is1hot. Thus an. override mechanism 334 may interconnect `the choke 'with the :heat valve link.- ages. .Thiszmechanism S34-includes a rod336 having'a lost motionconnection suehasan elongated slot 338" to permit relativeumovement of the two valves. Thus ywhen the engine'coolant iscold, the `spring 322will allow the bell crank 33910 rotate counterclockfwise and close the heat valve. ZFhiswillallowI the spring 302 to position the `choke val-ve `in response to the engine exhaust temperature because the slot 338 will allow therod 336:to move;

However; whenvthe engine coolantapproaches normal operating temperatures, the bell crank 330 will rotate clockwise 'therebyr opening the heat valve. A-t the same time the belll crankarm willengage the end of the slot 338and allot. the slack in the lost motion mechanism will be eliminated: Thus'eveu vthough the exhaust temperature is belownormali,- ,the rod 336 will' prevent the spr-in g S22-Y from movingv the lever 310-counterclockwise and opening the chokevalve.

It is to' be understood that, although the invention has een described with 4specificreference to particular embodiments thereof, it i-s not to be so limited since changes and alterations therein maybe made'which are within the full intended scope ofthis invention as defined bythe appended claims.

What is claimed is:

l. In an internal combustion engine having induction means, the. combination of an engine cooling system, an engine exhaust system, a choke valve for varying theairfuel ratio of the charge in said means, a heat valve for controlling the amount of-'he-at transferred from said'systems to said charge, thermostatic means responsive to the temperatures of both of said systems and a pair of links having the Vtirst ends-thereof operatively connected'tosaid thermostat-ic means, thejopposi'teen'd'of one of isaidlinks being connected'to oneY of said: valves'and the opposite end of the other of said links being connected to the other of said valves.

2. In an internal combustion engine having induction means, the combination of an engine cooling system, an engine exhaust system, a choke valve for varying the air-fuel ratio of the charge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, thermostatic means having a portion thereof responsive to the temperature of one of said systems and another portion responsive to the temperature of said other system, a common linkage interconnecting said valves with each other and with said thermostatic means.

3. In an internal combustion engine having induction means, the combination of an engine cooling system, an engine exhaust system, a choke valve for varying the air-fuel ratio of the charge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, a first thermostatic element responsive to the temperature of one of said systems and a second thermostatic element responsive to the temperature in the other of said systems, a common linkage operatively interconnecting said thermostatic elements with said valves, lost motion means actuated by one of said thermostatic elements to inactivate the other of said thermostatic elements when the temperature of the system associated with said next to last mentioned thermostatic element exceeds a predetermined amount.

4. In an internal combustion engine having induction means, the combination of an engine cooling system, an engine exhaust system, a choke valve for varying the airfuel ratio of the charge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, a irst thermostat responsive to the temperature in one of said systems, a second thermostat responsive to the temperature in the other of said systems, a pair of links having one end thereof operatively connected to one of said thermostats with the opposite end of one of said links being operatively connected to one of said valves and the opposite end of the other of said links being operatively connected to the other of said valves, stop means actuated by said second thermostat for preventing said first thermostat opening said valves when the temperature of the system associated with said second thermostat exceeds a predetermined amount.

5. In an internal combustion engine having induction means, the combination of an engine cooling system, an engine exhaust system, a choke valve for Varying the airfuel ratio of the charge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, a first thermostat responsive to the temperature of said exhaust system, a second thermostat responsive to the temperature of said cooling system, a iirst link interconnecting one of said thermostats with one of said valves and a second link interconnecting `the other of said thermostats with the other of said valves, lost motion means operatively interconnecting said thermostats with each other to prevent the operation of said first thermostat when the temperature of said cooling system exceeds a predetermined amount.

6. In an internal combustion engine having induction means, the combination of an engine cooling system, an

`engine exhaust system, a choke valve for varying the airfuel ratio of the charge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, a housing forming a chamber disposed in heat exchanging relation with said cooling sys- .tem and said exhaust system, a thermostatic element disposed in said chamber, common linkage means operatively interconnecting said thermostatic element with said valves.

7. In an internal combustion engine having induction means, the combination of an engine cooling system, an

for controlling the amount of heat transferred from said systems to said charge, a housing forming a chamber,a bale disposedY in said housing and dividing said chamber into two separate compartmens with one of said compartments being in heat exchanging relation with one of said systems andthe other of said compartments being in heat exchanging relation with the other of said systems, a first thermostatic element disposed in the first of said compartments and being operatively connected to said valves by a common linkage, a second thermostatic element disposed in the second of said compartments and being effective to prevent the operation of said first thermostatic element when the temperature of the system associated with said second compartment exceeds a predetermined amount.

8. ln an internal combustion engine having induction means, the combination of an engine cooling system, an engine exhaust system, a choke valve for varying the airfuel ratio of the charge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, a housing forming a chamber disposed in heat exchanging relation with said cooling system, duct means having one end thereof communicating with said chamber and having the other end thereof terminating adjacent said exhaust system, thermostatic means disposed in said chamber, and a common linkage operatively interconnecting both of said valves with said thermostatic means.

9. In an internal combustion engine having induction means, the combination of an engine cooling system, an engine exhaust system, a choke valve for varying the airfuel ratio of the charge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, a housing forming a chamber having one wall thereof disposed in heat exchanging relation with said cooling system, a thermostatic spring disposed in said housing, a common linkage operatively interconnecting said thermostatic spring with said valves, pneumatic means for tensioning said spring, a first duct having one end thereof communicating with said chamber and the other end thereof terminating `adjacent said exhaust system, a second duct having one end thereof communieating with said induction means and the other end thereof communicating with said pneumatic means.

10. In an internal combustion engine having induction means, the combination of an engine cooling system, an engine exhaust system, a choke valve for varying the air-fuel ratio of the charge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, a housing forming a chamber, a baflie disposed in said housing and dividing said chamber into two separate compartments, the first of said compartments being in heat exchanging relation with said cooling system, duct means having one end thereof cornmunicating with said second chamber and the other end thereof terminating adjacent said exhaust system, a irst thermostatic element disposed in the first of said compartments, a second thermostatic element disposed in the second of said compartments and being operatively connected to both of said valves by a common linkage, duct means having one end thereof communicating with said second chamber and having the other end thereof terminating adjacent said exhaust system, -a movable stop actuated by said lirst thermostatic element to prevent the operation of said first thermostatic element when the temperature of said cooling system exceeds a predetermined amount.

l1. The combination of claim 10 including pneumatic means for tensioning said second thermostatic element and second duct means having one end thereof communieating with said pneumatic means and the other end thereof communicating with said charge forming means.

l2. In an internal combustion engine having induction means, the combination of an engine cooling system, an engine exhaust system, a choke valve for varying the airfuel ratio of the vcharge in said means, a heat valve for controlling the amount of heat transferred from said systems to said charge, a housing forming a chamber, a thermostatic spring disposed in said chamber and being operatively connected to said heat valve for moving said heat valve between on and ofi positions, pneumatic means in said chamber for tensioning said spring, a first duct having one end thereof communicating with said pneumatic means and the other end thereof communicating with said induction means, a second duct having one end thereof communicating with said chamber and the other end thereof terminating adjacent said exhaust system, a second thermostatic spring disposed in heat exchanging relation with said cooling system and being operatively connected to said choke valve for moving said choke valve between on yand off positions, linkage means interconnecting said thermostatic springs and having lost m0- 10 tion means to prevent moving said heat valve to the on position when the temperature of said cooling system exceeds a predetermined amount.

13. ln an internal combustion engine having induction means, the combination of 'an engine cooling system, an engine exhaust system, a choke valve for varying the airfuel ratio of the charge in said means, a heat valve for controlling the amount of heat applied to said charge, a thermostatic element disposed in said cooling system and being responsive to the temperature thereof and a cornmon linkage interconnecting said valves with each other and with said thermostatic element.

References Cited in the le of this patent UNITED STATES PATENTS 2,094,165 Bicknell Sept. 28, 1937 

